I'm definitely no expert, but there are many foods high in protein that are low in fat and have no carbs, if your diet contains a lot of these foods and you are working out you should still be able to add mass while adjusting the proportions of protein vs. fat in your body
Some examples (of foods even I can find in Costa Rican grocery stores hehe):
- Low fat cottage cheese
- Egg supplement
- Ground beef for vegetarians (it's like ALL protein and fibre, not much carbs/fat)
- Low fat Tuna in water
- etc...
I'm sure where you live you can find tons more.